A circularly polarized millimeter wave lens antenna device

Abstract

The present invention relates to the field of millimeter wave antennas, and specifically to a circularly polarized millimeter wave lens antenna device, comprising a base, a dielectric lens, a horn antenna and a feed source; the feed source comprises a first layer of copper foil, a second layer of copper foil, a third layer of copper foil and a fourth layer of copper foil; a microstrip patch antenna is arranged on the first layer of copper foil; a square hole is arranged on the second layer of copper foil; the third layer of copper foil, the fourth layer of copper foil, a dielectric plate C and a metallized blind hole array constitute an L-shaped substrate integrated waveguide; two orthogonal slits are arranged on the third layer of copper foil; a Langer 3dB coupler is arranged on the fourth layer of copper foil, and its 0° / 90° port is connected to both ends of the L-shaped substrate integrated waveguide; the dielectric lens is connected to the base; and the horn antenna is connected to the dielectric plate A. The present invention can realize circular polarization, high gain, narrow beam, low side lobe and wide bandwidth of the antenna to improve the performance of the radar system.

Description

Technical Field

[0001] The invention relates to the field of millimeter wave antennas, and in particular to a circularly polarized millimeter wave lens antenna device. Background Art

[0002] In complex environments, in order to improve radar measurement accuracy and distinguish multipath frequency components from other target interference frequency components, in addition to using more complex radar signal processing algorithms, the antenna can be improved through the following measures: narrowing the antenna beam to improve the spatial resolution of the radar system; increasing the antenna gain to improve the signal carrier-to-noise ratio; improving the antenna impedance and gain bandwidth to allow a wider sweep bandwidth and improve the distance resolution; using circularly polarized antennas and polarization isolation to improve the radar system's ability to resist multipath interference; however, in the millimeter wave frequency band, using traditional microstrip array antennas, the printed dielectric board and copper foil have large losses, making it difficult to achieve high gain; beam sidelobe suppression requires high processing accuracy; the larger the antenna array, the narrower the gain and impedance bandwidth, which is not conducive to increasing the sweep bandwidth; the design of the circularly polarized antenna array feed network is complex; high gain and narrow beam require the size of the printed dielectric board to increase exponentially, resulting in rising costs;

[0003] Patents with authorization announcements CN104701633A and CN109768374A disclose methods of using dielectric lenses to achieve high gain, broadband and narrow beams. However, the dielectric lenses are too thick, which is not conducive to mass production and cost reduction through mold opening and injection molding processes, and is not convenient for integration with other active circuits, and circular polarization is not achieved. Summary of the invention

[0004] The purpose of the present invention is to address the problems existing in the background technology and to propose a circularly polarized millimeter-wave lens antenna device that realizes circular polarization, high gain, narrow beam, low side lobe and wide bandwidth of the antenna to improve the performance of the radar system.

[0005] The technical solution of the present invention: A circularly polarized millimeter wave lens antenna device comprises a base, a dielectric lens, a horn antenna and a feed source;

[0006] The feed source comprises a dielectric plate A, a dielectric plate B and a dielectric plate C; the dielectric plates A, B and C are stacked and connected in sequence; the upper end surface of the dielectric plate A, between the dielectric plates A and B, between the dielectric plates B and C, and the lower end surface of the dielectric plate C are respectively provided with a first layer of copper foil, a second layer of copper foil, a third layer of copper foil and a fourth layer of copper foil;

[0007] A microstrip patch antenna is provided on the first layer of copper foil;

[0008] A square hole with a side length of 2λ0 is provided on the second layer of copper foil, and the square hole is located directly below the microstrip patch antenna; where λ0 is the wavelength in free space;

[0009] The third copper foil layer, the fourth copper foil layer, the dielectric plate C and the metallized blind hole array constitute an L-shaped substrate integrated waveguide; the length of the L-shaped substrate integrated waveguide is 4λ g , with a width of 0.75λ g , where λ g is the wavelength of the dielectric waveguide; the L-shaped substrate integrated waveguide is parallel to the side of the microstrip patch antenna, and the center of the corner of the L-shaped substrate integrated waveguide coincides with the center of the microstrip patch antenna;

[0010] There are two orthogonal slits on the third copper foil layer; the center of the cross slit coincides with the center of the microstrip patch; the length of the cross slit is 0.5λ g , width 0.05λ g ;

[0011] A Langer 3dB microstrip coupler is provided on the fourth layer of copper foil, and its 0° / 90° port is connected to the two ends of the L-shaped substrate integrated waveguide. The common end input signal or the isolation end input signal is used to excite the microstrip patch antenna to form a left-handed or right-handed circularly polarized electromagnetic field; wherein, the L-shaped substrate integrated waveguide uses a symmetrical trapezoidal gradient structure to transform the waveguide into a microstrip line, and transforms it into a 50Ω microstrip line;

[0012] The dielectric lens is connected to the base, and the outer surface of the dielectric lens is an elliptical surface, wherein the feed source is located at the distal focus of the elliptical surface of the dielectric lens, and the distance between the feed source and the distal focus of the elliptical surface of the dielectric lens is f, f=16λ0;

[0013] The inner surface of the dielectric lens is a spherical surface, and the distance from the spherical surface of the dielectric lens to the feed source is r, where: ε r The dielectric constant of the material used to prepare the dielectric lens; ψ max is the maximum radiation half angle of the dielectric lens;

[0014] The maximum thickness of the dielectric lens is h max , where h max =fr;

[0015] The horn antenna is located between the dielectric lens and the feed source, the horn antenna is connected to the dielectric plate A, and is located directly above the microstrip patch antenna.

[0016] Preferably, the dielectric lens is made of polycarbonate material, and the dielectric constant ε of the dielectric lens is r =3.

[0017] Preferably, the maximum radiation half angle ψ of the dielectric lens max =22.5°.

[0018] Preferably, the microstrip patch antenna has a length and width of 0.92 mm and resonates at 79 GHz.

[0019] Preferably, the horn antenna has a 3dB beam width of ±12°.

[0020] Preferably, the horn antenna is made of aluminum.

[0021] Preferably, the base is made of polycarbonate.

[0022] Compared with the prior art, the above technical solution of the present invention has the following beneficial technical effects:

[0023] The circularly polarized millimeter wave lens antenna device provided by the present invention adopts a feed source made of a multi-layer high-frequency printed circuit board, which is convenient for integration with other active circuits. The signal is orthogonally excited to the substrate integrated waveguide through a microstrip polarization feeding network, coupled to the microstrip patch antenna through a cross slot, and the radiated electromagnetic waves are directionally transmitted and received through a horn antenna and a dielectric lens, thereby realizing circular polarization, narrow beam, high gain, low side lobe, wide bandwidth and anti-multipath interference of the antenna to improve the performance of the radar system; the circularly polarized millimeter wave lens antenna device has the advantages of low manufacturing cost and convenience for industrial production, and is worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a schematic structural diagram of an embodiment of the present invention.

[0025] Figure 2 for Figure 1 Schematic diagram of the structure of the medium feed source.

[0026] Figure 3 for Figure 2 Center feed source diagram.

[0027] Figure 4 This is the standing wave ratio diagram of the 79GHz lens antenna device.

[0028] Figure 5 This is the radiation pattern of the 79GHz lens antenna device.

[0029] Figure 6 This is the axial ratio diagram of the 79GHz lens antenna device.

[0030] Figure numerals: 1, base; 2, dielectric lens; 3, horn antenna; 4, feed source; 41, dielectric plate A; 42, dielectric plate B; 43, dielectric plate C; 401, first layer of copper foil; 402, second layer of copper foil; 403, third layer of copper foil; 404, fourth layer of copper foil. DETAILED DESCRIPTION

[0031] Embodiment 1

[0032] like Figure 1-3As shown, a circularly polarized millimeter wave lens antenna device proposed in the present invention includes a base 1, a dielectric lens 2, a horn antenna 3 and a feed source 4;

[0033] The feed source 4 includes a dielectric plate A41, a dielectric plate B42 and a dielectric plate C43; the dielectric plates A41, B42 and C43 are stacked and connected in sequence; the upper end surface of the dielectric plate A41, between the dielectric plates A41 and B42, between the dielectric plates B42 and C43, and the lower end surface of the dielectric plate C43 are respectively provided with a first layer of copper foil 401, a second layer of copper foil 402, a third layer of copper foil 403 and a fourth layer of copper foil 404;

[0034] The thickness of the first copper foil 401 and the fourth copper foil 404 is 35 μm; the thickness of the second copper foil 402 and the third copper foil 403 is 18 μm;

[0035] The dielectric board A41 uses RO3003, the dielectric constant ε r1 =3, thickness 0.127mm;

[0036] The dielectric board B42 uses RO4450F, which is a prepreg sheet with a dielectric constant of ε r1 =3.52, thickness 0.3mm;

[0037] The dielectric board C43 uses RO3003, the dielectric constant ε r1 =3, thickness 0.127mm;

[0038] The first copper foil 401, dielectric board A41, second copper foil 402, dielectric board B42, third copper foil 403, dielectric board C43 and fourth copper foil 404 are pressed by a printing process to obtain a printed circuit board to realize the circuit function;

[0039] A microstrip patch antenna is provided on the first copper foil 401; the length and width of the microstrip patch antenna are both 0.92 mm, and the resonance is 79 GHz;

[0040] A square hole with a side length of 2λ0 is provided on the second copper foil 402, and the square hole is located directly below the microstrip patch antenna; wherein λ0 is the wavelength in free space;

[0041] Furthermore, the square holes on the second copper foil 402 are obtained by etching, and the square holes are provided so that energy can be coupled from the gap of the substrate integrated waveguide to the microstrip patch antenna;

[0042] The third copper foil 403, the fourth copper foil 404, the dielectric plate C43 and the metallized blind hole array constitute an L-shaped substrate integrated waveguide; the diameter of the metallized blind hole is 0.15 mm, and the distance between the metallized blind holes is 0.3 mm; the metallized blind hole array is obtained when the third copper foil 403, the fourth copper foil 404 and the dielectric plate C43 are pressed into a printed circuit board;

[0043] The L-shaped substrate integrated waveguide has a length of 4λ g , with a width of 0.75λ g , where λ g is the wavelength of the dielectric waveguide; the L-shaped substrate integrated waveguide is parallel to the side of the microstrip patch antenna, and the center of the corner of the L-shaped substrate integrated waveguide coincides with the center of the microstrip patch antenna;

[0044] The third copper foil 403 is provided with two orthogonal slits for electromagnetic waves to penetrate through the cross slits; the center of the cross slit coincides with the center of the microstrip patch antenna; the length of the cross slit is 0.5λ g , width 0.05λ g ;

[0045] A Langer 3dB microstrip coupler is provided on the fourth copper foil 404, and its 0° / 90° port is connected to the two ends of the L-shaped substrate integrated waveguide, and the common end input signal or the isolation end input signal is used to excite the microstrip patch antenna to form a left-handed or right-handed circularly polarized electromagnetic field; in a single-station radar, the common end is connected to the transmitting channel / receiving channel, and the isolation end is connected to the receiving channel / transmitting channel;

[0046] Among them, one end of the L-shaped substrate integrated waveguide uses a symmetrical trapezoidal gradient structure to transform the waveguide to the microstrip line. The gradient structure length is 0.82mm, the width of the substrate integrated waveguide end is 0.7mm, and the other end is a 50Ω microstrip line with a width of 0.29mm.

[0047] When circularly polarized electromagnetic waves are reflected by an object, the polarization mode is reversed. In a single-station radar, the common end excites left-handed / right-handed electromagnetic waves to be transmitted, and the reflected waves on the target direct path have the opposite polarization to the transmitted electromagnetic waves. The isolation end receives right-handed / left-handed electromagnetic waves, and the electromagnetic waves generated by the even-second rebound have polarization isolation, which has the ability to resist multipath interference.

[0048] The dielectric lens 2 is connected to the base 1, and the outer surface of the dielectric lens 2 is an elliptical surface, wherein the feed source 4 is located at the distal focus of the elliptical surface of the dielectric lens 2, and the distance between the feed source 4 and the distal focus of the elliptical surface of the dielectric lens 2 is f, and f=16λ0;

[0049] The inner surface of the dielectric lens 2 is a spherical surface, and the distance from the spherical surface of the dielectric lens 2 to the feed source 4 is r, where: ε rThe dielectric constant of the material prepared for the dielectric lens 2; ψ max is the maximum radiation half angle of dielectric lens 2;

[0050] Furthermore, the dielectric lens 2 is made of polycarbonate material, and the dielectric constant ε of the dielectric lens 2 is r =3; Maximum radiation half angle ψ of dielectric lens 2 max =22.5°;

[0051] The maximum thickness of dielectric lens 2 is h max , where h max =fr;

[0052] The horn antenna 3 is located between the dielectric lens 2 and the feed source 4. The horn antenna 3 is connected to the dielectric plate A41 and is located directly above the microstrip patch antenna.

[0053] Furthermore, the horn antenna 3 is made of aluminum, and the horn antenna 3 has a 3dB beam width of ±12°. The horn antenna 3 is fixed to the high-frequency printed medium board with screws to improve the directivity of the feed source, reduce the leakage and diffraction of electromagnetic waves, reduce the thickness of the dielectric lens, facilitate mold opening and injection molding, and reduce costs;

[0054] The base 1 is made of polycarbonate material. The base 1 is a structure with a cavity obtained by injection molding. The feed source 4 is installed at the bottom of the cavity of the base 1. The dielectric lens 2 is installed on the upper end surface of the cavity of the base 1 by bolts. The microstrip patch antenna is located at the distal focus of the elliptical surface of the dielectric lens 2, that is, at the center of the inner spherical surface of the dielectric lens 2.

[0055] Embodiment 2

[0056] like Figure 4-6 As shown, an application of a circularly polarized millimeter wave lens antenna device proposed by the present invention includes the circularly polarized millimeter wave lens antenna device in the first embodiment, and the circularly polarized millimeter wave lens antenna device is used in the 79 GHz wave frequency band to transmit and receive electromagnetic wave signals;

[0057] Then, the center frequency is 79GHz;

[0058] Bandwidth: ≥7GHz;

[0059] Gain: ≥25dB;

[0060] 3dB beam width: ≤±3°;

[0061] Standing wave ratio: ≤2;

[0062] Sidelobe suppression ≥: 20dB;

[0063] Axis ratio: ≤1dB.

[0064] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A circularly polarized millimeter wave lens antenna device, characterized in that: It comprises a base (1), a dielectric lens (2), a horn antenna (3) and a feed source (4); The feed source (4) comprises a dielectric plate A (41), a dielectric plate B (42) and a dielectric plate C (43); the dielectric plates A (41), B (42) and C (43) are stacked and connected in sequence; the upper end surface of the dielectric plate A (41), between the dielectric plates A (41) and B (42), between the dielectric plates B (42) and C (43) and the lower end surface of the dielectric plate C (43) are respectively provided with a first layer of copper foil (401), a second layer of copper foil (402), a third layer of copper foil (403) and a fourth layer of copper foil (404); A microstrip patch antenna is provided on the first layer of copper foil (401); A square hole with a side length of 2λ0 is provided on the second copper foil (402), and the square hole is located directly below the microstrip patch antenna; wherein λ0 is the wavelength in free space; The third layer of copper foil (403), the fourth layer of copper foil (404), the dielectric plate C (43) and the metallized blind hole array constitute an L-shaped substrate integrated waveguide; the length of the L-shaped substrate integrated waveguide is 4λ g , with a width of 0.75λ g , where λ g is the wavelength of the dielectric waveguide; the L-shaped substrate integrated waveguide is parallel to the side of the microstrip patch antenna, and the center of the corner of the L-shaped substrate integrated waveguide coincides with the center of the microstrip patch antenna; The third layer of copper foil (403) is provided with two orthogonal slits; the center of the cross slit coincides with the center of the microstrip patch antenna; the length of the cross slit is 0.5λ g , width 0.05λ g ; A Langer 3dB microstrip coupler is arranged on the fourth copper foil layer (404), and its 0° / 90° port is connected to the two ends of the L-shaped substrate integrated waveguide, and the common end input signal or the isolation end input signal is used to excite the microstrip patch antenna to form a left-handed or right-handed circularly polarized electromagnetic field; wherein the L-shaped substrate integrated waveguide uses a symmetrical trapezoidal gradient structure to transform the waveguide into a microstrip line, and transforms it into a 50Ω microstrip line; The dielectric lens (2) is connected to the base (1), and the outer surface of the dielectric lens (2) is an elliptical surface, wherein the feed source (4) is located at the far end focus of the elliptical surface of the dielectric lens (2), and the distance between the feed source (4) and the far end focus of the elliptical surface of the dielectric lens (2) is f, f=16λ0; The inner surface of the dielectric lens (2) is a spherical surface, and the distance between the spherical surface of the dielectric lens (2) and the feed source (4) is r, where: ε r The dielectric constant of the material used to prepare the dielectric lens (2); ψ max is the maximum radiation half angle of the dielectric lens (2); The maximum thickness of the dielectric lens (2) is h max , where h max =fr; The horn antenna (3) is located between the dielectric lens (2) and the feed source (4). The horn antenna (3) is connected to the dielectric plate A (41) and is located directly above the microstrip patch antenna.

2. A circularly polarized millimeter wave lens antenna device according to claim 1, characterized in that: The dielectric lens (2) is made of polycarbonate material, and the dielectric constant ε of the dielectric lens (2) is r =3.

3. The circularly polarized millimeter wave lens antenna device according to claim 1, characterized in that: The maximum radiation half angle ψ of the dielectric lens (2) max =22.5°.

4. The circularly polarized millimeter wave lens antenna device according to claim 1, characterized in that: The length and width of the microstrip patch antenna are both 0.92mm, and it resonates at 79GHz.

5. The circularly polarized millimeter wave lens antenna device according to claim 1, characterized in that: The horn antenna (3) has a 3dB beam width of ±12°.

6. The circularly polarized millimeter wave lens antenna device according to claim 1, characterized in that: The horn antenna (3) is made of aluminum.

7. The circularly polarized millimeter wave lens antenna device according to claim 1, characterized in that: The base (1) is made of polycarbonate material.

Images